81288725416920 has 320 divisors, whose sum is σ = 312293725286400. Its totient is φ = 18577793076480.

The previous prime is 81288725416907. The next prime is 81288725417033. The reversal of 81288725416920 is 2961452788218.

81288725416920 is a `hidden beast` number, since 8 + 1 + 2 + 8 + 8 + 7 + 2 + 541 + 69 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 171927801 + ... + 172399959.

It is an arithmetic number, because the mean of its divisors is an integer number (975917891520).

Almost surely, 2^{81288725416920} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81288725416920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156146862643200).

81288725416920 is an abundant number, since it is smaller than the sum of its proper divisors (231004999869480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81288725416920 is a wasteful number, since it uses less digits than its factorization.

81288725416920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479780 (or 479767 counting only the distinct ones).

The product of its (nonzero) digits is 30965760, while the sum is 63.

The spelling of 81288725416920 in words is "eighty-one trillion, two hundred eighty-eight billion, seven hundred twenty-five million, four hundred sixteen thousand, nine hundred twenty".